1. Field of the Invention
The present invention relates generally to computer networks, and more particularly but not exclusively to peer-to-peer data transfers.
2. Description of the Background Art
Peer-to-peer (“P2P”) refers to computer networking that allows one computer to directly communicate with another computer with little or no assistance from a central server. P2P networks are widely employed in both home and business environments to transfer data, such as files for music, word processing, spreadsheet, video, and so on. Although P2P networks may have varying implementation details, most P2P networks allow files to be transferred directly from one computer to another. P2P networks may be implemented on the Internet. On the Internet, a P2P network typically requires the services of a P2P server to provide a directory of computers, referred to herein as “P2P clients,” that have a particular file. A P2P client identified as having the particular file may provide that file directly (i.e., without going through an intermediary computer) to another P2P client in a P2P data transfer.
One problem with P2P networks is that direct data exchange between two P2P clients may facilitate transfer of computer viruses. Viruses are especially problematic in P2P networks operating over the Internet because there are a lot of P2P clients that are operated by unknown individuals, who may not have antivirus in their computers or have malicious intentions (e.g., hackers, virus coders). Techniques for protecting computers from viruses in P2P data transfers are thus generally desirable.